The official unit of currency is the Iranian rial, but Iranians almost always talk in terms of tomans, a unit equal to 10 rials. The sooner you get your head around the idea of tomans, the better. However, with inflation soaring and the Central Bank of Iran openly discussing wiping three or four zeroes off the rial or doing away with the currency completely, we usually convert all prices into US dollars. The idea is that as rial inflation rises, prices should remain relatively steady in dollar terms.For all intents and purposes, Iran for the visitor is a purely cash economy. No credit cards. No travellers cheques. Just bring cold, hard cash – preferably in high-denomination euros or US dollars printed since 1996. Apart from some hotels, carpet shops and tour agencies where you can pay in dollars or euros, all transactions are in rials. Where prices are quoted in euros we will do the same. Other major currencies, such as British pounds, Australian or Canadian dollars, Swiss francs and UAE dirhams, can be changed in Tehran and other big cities, if not smaller towns.